| 摘要 |
PURPOSE:To obtain an isotropic film having both of excellent heat resistance and excellent mechanical properties, by casting an optically anisotropic or flow-birefringent dope of a specified polymer on a flat plane and coagulating it after heating or humidification. CONSTITUTION:An optically anisotropic or flow-birefringent dope of a polymer having repeating units of formula I or II or of a copolymer comprising repeating units of formulas I and II is cast on a flat plane and coagulated after heating and/or humidification to obtain a film comprising a heteroaromatic polymer. In the formulas, Ar is formula III or any one of halogen-, alkyl-, cyano-, nitro- or alkoxy-substituted products thereof, and said polymer may be a copolymer having at least two kinds of Ar groups. The obtained film is one having a ratio between the tensile strengths along two arbitrarily selected rectangular directions in the range of 0.4-2.5.
|
